1. Field of the Invention
The present invention pertains to a large, self-contained and self-propelled oil spill recovery and storage ship for recovering relatively large quantities of oil or other floating liquid pollutants as would be encountered in a large-scale marine oil spill, well blow-out or pipeline rupture.
2. Background
As described in U.S. Pat. No. 5,047,156 issued Sep. 10, 1991, to John L. Sullivan and assigned to the assignee of the present invention, several proposals for oil spill recovery ships have been disclosed in the prior art including those described in U.S. Pat. Nos. 3,690,464 to Heinicke, 3,744,257 to Spanner, 3,847,816 to DePerna, 3,884,807 to Heddon, 3,929,644 to Fletcher, 3,966,615 to Petchul et al, 4,033,876 to Cocjin et al, 4,067,811 to Dallamore, 4,120,793 to Strain, 4,257,889 to Wober et al, 4,308,140 to Pierson, Jr., and 4,653,421 to Ayers. These patents disclose various systems, some of which are alleged to be capable of open ocean recovery of floating oil.
The above-mentioned patent to Sullivan describes a large-scale oil recovery vessel having opposed bow doors which open to allow oily water to enter a sluiceway for skimming oil from the water by the adjustment of a weir disposed in the sluiceway. The ship described in the patent application also includes an improved storage and decanting system. This vessel is capable of ingesting and processing large quantities of oil-covered sea water wherein the oil layer may be up to several inches thick and wherein the sea state may be something greater than calm during recovery operations.
Experience with prior art oil recovery methods and devices has revealed that a ship capable of recovering large quantities of oil must also be capable of storage of large quantities of oil in order to effectively recover a spill before significant environmental damage occurs. In this regard, shipboard oil and water handling facilities should be arranged such that a minimal amount of mixing of water and oil occur. If this objective is not achieved, the oil separation and storage capacity is severely limited even in a large vessel such as a very large crude carrier.
Although the recovery vessel described in U.S. Pat. No. 5,047,156 has significant separation and storage facilities, it has been determined that a wider swath of oil should be recovered with each pass of the vessel through the oil slick than is typically easily achieved with a vessel having the bow door and booming arrangement described in the aforementioned patent application. Just as important, perhaps, is the requirement that the vessel, when not being used for oil spill recovery and storage, be capable of serving as a liquids carrier in commercial trade, or at least as a floating storage vessel. In this regard, modification of conventional liquids carriers as provided for in the aforementioned patent application is not as effective as a modification of an existing or conventional liquids carrier in accordance with the present invention.
Accordingly, it has been determined that it is important to be able to efficiently convert a conventional liquids carrier having multiple liquid cargo and ballast tanks to an effective oil spill recovery and storage ship while minimizing the structural modification to the ship. Concomitantly, it is important to provide an effective oil recovery system which (1) will minimize the amount of oily water which must be handled by the ship, (2) is capable of recovering relatively large spills in the open ocean as well as in more protected waters, and (3) is capable of settling relatively large quantities of oily water to allow gravitational separation before final processing and storage of the oil.
The present invention meets the desiderata mentioned herein in accordance with the summary and detailed description set forth below.